Interface members for connecting a given electrical component to another electrical component or a given package to another package are used in a vehicle such as an automobile or an electronic device such as a household electrical appliance.
As a typical interface member, a so-called wire harness is available, which is formed by binding a plurality of electric wires or communication lines into a bundle by using a protective member such as a tape as needed and attaching predetermined connectors to the two end portions of the bundle. Wire harnesses differ in the numbers of electric wires and the thickness of each electric wire, and some wire harnesses have branch points while others do not have any wire harnesses in accordance with application purposes (connection destinations). Therefore, the wire harnesses vary in rigidity.
At the maker site of design frequently using such wire harnesses, CAD (Computer-Aided Design) systems have been widely used for design of electrical components, packages, and the like at an earlier time. In general, however, for design of wire harness wiring routes, lengths, the number of electric wires or communication lines to be bound into a bundle, and the like, a designer repeatedly forms prototypes mainly on the basis of intuition and experiences.
Recently, however, to develop a product in a short period of time with the minimum number of prototypes actually formed, a series of design operations have been performed on a design support apparatus using a computer and the like. In designing the above wire harness, demand has arisen for a support apparatus which can facilitate optimal design regardless of designer's experience.
With such need as a background, in current CAD systems, a function has been developed, which automatically calculates a curve or curved surface that satisfies (approximates) a plurality of points (coordinates) defined on a two-dimensional plane or three-dimensional space by an operator by using a parametric technique using a B-Spline curve, Bezier curve, NURBS curved surface, or the like.
Shape simulations based on these methods satisfy the coordinate data of a plurality of fixed points. However, these simulations are performed by geometric processing. If, therefore, such a simulation is applied to, for example, the design of wire harness wiring, since no consideration is given to the weight and hardness (rigidity) of the wire harness and dynamic factors such as force produced at fixed positions such as connectors due to these factors, it is often difficult (impractical) to directly manufacture an actual product in accordance with the generated shape.
As one of the parametric techniques described above, a method of performing a simulation of the shape of a wire harness disposed along an arm of an industrial robot is disclosed in Japanese Patent Laid-Open No. 7-182017.
In this method, the shape of a wire harness as a simulation target which deforms as an arm of a robot moves is automatically calculated on the basis of parameters, input by an operator, such as a plurality of fixed point positions on the arm, tangent vectors at the fixed position positions, the length of the wire harness, and the modulus of deformation. This makes it possible to check interference between the arm and surrounding apparatuses.
In the prior art described above, however, no consideration is given to semifixed support members (clips) for fixing the wire harness, branch portions provided for the same wire harness, forces that are produced at the respective fixed points as the wire harness bends, and the like.
In addition, in the automatically calculated shape of a wire harness, the forces acting on connectors and the like on the two end portions of the wire harness are not clarified, it is difficult to grasp, for example, how much strength is necessary or appropriate in fixing the wire harness.